Initial testing setup

[thekaveman]

Depends on #5

• New dependency type test in pyproject.toml

• Add dependencies

  "coverage",
  "pytest",
  "pytest-django",
  "pytest-mock",
  "pytest-socket",
  

• Create tests/pytest directory

• Create a test file and a test that requests a /healthcheck endpoint from the app and asserts a 200 response code and "Healthy" response text

• Implement this endpoint in the Django app so the test passes

• Create a GitHub Actions workflow to run pytests on push and pull_request, upload coverage report, comment w/coverage report

[thekaveman]

@lalver1 you may want to do #33 first